Lip seals



June 18, 1968 R. MQKINVEN, JR 3,388,456

LIP SEALS Original Filed Jan. 8. 1964 4 Sheets-Sheet 1 E /0 3 I 27 Q 4/mvsmox. ROBERT M0 K/NVEN, JR. M W

June 18, 1968 R. MCKMEN, R 3,388,456

LIP SEALS Original Filed Jan. 8, 1964 4 Sheets-Sheet '3 f 9 gm INVENTOR.ROBERT M0 K l/VVE N. JR.

KINVEN, JR

LIP SEALS 4 Sheets-Sheet 3 June 18, 1968' R. IMGKINVEN, JR 3,388356 LIPSEALS 4 Sheets-Sheet 4 Original Filed Jan; 8, 1964 7 Q Q a g 9 ii, Q

H H INVENTOR.

ROBERT/W? K/NVEN. JR. HMM

United States Patent (Mike 6 Claims. (Cl. 29--528) This application is adivision of Ser. No. 336,532, filed J an. 8, 1964, now US. Patent No.3,276,783, which was a continuation-in-part of my copending application,Ser. No. 178,390, filed Mar. 8, 1962, now U.S. Patent No. 3,250,541.

This invention relates to a new and improved shaft seal and an improvedmethod of manufacturing the same. More specifically, the invention isdirected to the solution of problems encountered in the internalgasketing of seals, especially those formed of fluorocarbon, and furtherto effectively provide a flexible manner of attaching a sealing elementor elements formed from diverse or like materials to a relativelystandardized casing in order to minimize the cost of manufacture whileproviding a wide range of seal types.

It is a principal object of this invention to provide a new and improvedshaft seal.

It is a further object of this invention to provide an improved meansfor attaching a sealing element or elements to a casing in a fluidtightmanner.

It is a further object of this invention to provide a novel pressuremeans to hold sealing elements of formed relatively stiff materials to acasing.

It is a further object of this invention to provide a multilip sealarrangement wherein the lip seal elements are supported for independentsealing action by a common casing.

It is a further object of this invention to provide a shaft seal withplural sealing lips of diverse materials wherein one sealing lip,although independent of the other, serves to provide an internal gasketfor the other lip with both of the sealing lips being supported by acommon casing.

It is a further object of this invention to provide a shaft sealembodying a casing supporting a flash free bonded lip structure as wellas a fluorocarbon sealing element which is clampingly received injuxtaposition to the molded lip structure and gasketed thereby.

It is a further object of this invention to provide a novel pressureflange means which is uniquely clamped in a casing so as to establish aforce couple which continuously exerts pressure on the sealing elementsalso clamped in the casing.

It is a further object of this invention to provide a new and improvedmethod of manufacture of a shaft seal assembly including a method offlash free attachment of a sealing lip element to a peripheral portionof a casing.

Further and fuller objects will become readily apparent when referenceis made to the accompanying drawings wherein:

FIG. 1 is an enlarged half sectional view of a seal employing a doublelip structure;

FIG. 2 is an enlarged half sectional view illustrating a modification ofthe embodiment of FIG. 1;

FIG. 3 is an enlarged half sectional view of an embodiment similar toFIG. 1 utilizing a separate inner cup;

FIG. 4 is a view similar to FIG. 3 illustrating-a duplicate lipstructure with a clamped elastomeric packing;

FIG. 4A is a fragmentary half section similar to the construction ofFIG. 3 with the omission of the molded lip structure and pressureflange;

3,388,456 Patented June 18, 1968 FIG. 4B is a cross sectional viewsimilar to FIG. 4A including a modified form of pressure flange;

FIG. 5 is an enlarged half sectional view of the outside casing of theembodiments of FIGS. 3 and 4;

FIG. 6 is a half section of the casing of FIG. 5 after assembly of theinner cup with a modified form of inner cup shown in dotted lines;

FIG. 7 is an enlarged half sectional view of the casing of FIG. 6 withthe molded lip portion;

FIG. 8 is the device of FIG. 7 with the additional packing element andretainer flange added prior to clamping;

FIG. 9 is a half sectional view of the casing of the embodiment of FIG.1 after forming;

FIG. 10 is a half section of the casing of FIG. 1 with the radiallydirected leg portion in contacting engagement with. the radial faceportion;

FIG. 11 is a view similar to FIG. 10 with a lip molded integral with theinner peripheral portion;

FIG. 12 is a view similar to FIG. 11 with a pressure flange and anadditional sealing element in the assembled position prior to clamping;

FIG. 13 is a fragmentary elevational view of the pressure flange;

FIG. 14 is a cross sectional view of the pressure flange with dottedlines to show the configuration taken when assembled;

FIG. 15 is an enlarged half section of a mold with the mold halves incontact with a casing member such as that shown in FIG. 9;

FIG. 16 is the mold of FIG. 15 in the closed position;

FIG. 17 is an enlarged fragmentary view of the mold at the seal casingcontacting portion with the casing shown in dotted lines prior tocomplete closing of the mold;

FIG. 18 is an enlarged half section of a mold with halves at initialcontact with the casing of FIG. 6;

FIG. 19 illustrates the mold in the closed position with dotted lines toillustrate acceptance of a modified form of casing; and

FIG. 20 is a half section of a modified form of seal utilizing thecasing of FIG. 6.

The embodiment shown in FIG. 1 illustrates a sealing member 10 includinga seal mounting member 11 having a cylindrical peripheral portion 12terminated at one end in an abbreviated rolled over flange portion 13.In some environments the cylindrical peripheral portion would be omittedin lieu of other means to attach the seal member to a shaft or casing,however, for convenience the present application will be described inconnection with the mounting member shown. At the opposite end of thecylindrical peripheral portion 12 a second flange portion 14 extendsradially inwardly providing a pair of of axially facing radiallyextending face portions 15 and 16, and terminating at its innerperiphery in a generally U-shaped portion 17. The U-shaped portion 17extends radially outwardly and curls over smoothly as at 18 to define aseal element mounting groove 19. The seal element mounting groove 19 isprovided with a relatively narrow mouth portion formed by an axiallyraised portion 20, and a generally radially extending leg portion 21.

A sealing element 22 is bonded to the base of the U- shaped portion 17by a novel flashless method to be described hereinafter and has aportion extending upwardly across the axially raised portion 20 of themouth ultimately terminating in the groove 19 thereby forming athickened elastomeric portion 23 completely across the axially raisedportion 20. A second sealing element 24 is also positioned within thegroove in overlying juxta posed relationship to the thickened portion 23and is held thereto by means of a pressure flange 25 which extendsthrough the mouth portion into the groove 19. The radially extending leg21, defining one side of the mouth portion, is curled over at assemblyapplying axial force to an outer peripheral portion of the pressureflange 25 so as to continuously exert pressure thereon thereby clampingthe sealing element 24 into fluidtight engagement with the thickenedelastomer portion 23 covering the axially raised portion 20. Theapplication of force to the outer peripheral portion of the pressureflange 25 in the manner noted above serves to distort it from a purelyradial position since the axially raised portion 20, acting through thelayer of elastomer at 23 and the sealing element 24, resists furtheraxial movement of the inner peripheral portion of the pressure flange25. Thus the pressure flange forces the sealing element 24 towards theraised portion 20 to form a fluidtight joint.

When the pressure flange 25 is examined in a free body diagram, oneforce, representing the clamping force, will be exerted axially againstthe outer peripheral portion in one direction while a resisting force,representing the force opposing axial movement of the inner peripheralportion of the pressure flange, will be exerted generally adjacent theinner peripheral portion in an opposite direction to the first forcethereby establishing a force couple. As will be described hereinafter ingreater detail, the use of a force couple provides substantial benefitsin that continuous clamping pressure is exerted against the sealingelement 24 urging it into compressing engagement with the elastomercovering the raised portion 20 to maintain a fluidtight gasket conditionwhich is effective over a wide range of temperatures and pressures.

A modified form of seal is illustrated in FIG. 2, includ ing a sealmounting member 26 having an axially extending portion 27 and agenerally radially extending portion 28. The radially extending portion28 is offset as at 29 to rigidify the radial portion 28, as well asrecess the seal mounting groove 30 a slight amount for purposes tobecome apparent. The seal mounting groove is constructed in the mannerof the arrangement of FIG. 1 having the mouth portion defined by anaxially raised portion 31 and generally radially extending clamping legportion 32.

A sealing element 33 having a thickened inner peripheral portion '34 isreceived in the groove 30, with a second sealing element 35 positionedadjacent the sealing element 33. Both sealing elements are clamped influidtight engagement between the mouth portions of the groove throughinterposition of a pressure flange 36 to establish a force couplerelationship in the manner described in connection with FIG. 1. Anaxially extending annular portion 37 on the pressure flange 36rigidifies the inner periphery to also resist bending when the legportion 32 is rolled over to clamp the pressure flange and sealingelements into fluidtight engagement in the groove 30. The axiallyextending portion on the pressure flange also acts as a protector forthe fluorocarbon lip during shipment and handling. Obviously, theaxially extending portion of the flange 37 may be omitted in lieu of aheavier gauge of material being used for a pressure flange.

The sealing element 35 may be formed of a suitable elastomer capable ofbeing deformed under pressure, thereby providing a resilient backing forthe sealing element 33, as well as forming an exclusionary lip forsealing engagement with a shaft. During shipment and handling, the lipof the element 35 is protected at all times since it is positionedwithin the axial dimensions of the annular casing member. It iscontemplated that the sealing element 34 will be pierced to provide aninternal dimension smaller than the shaft of intended use, as is truewith the embodiment of FIG. 1. Considerable kinetic energy at thesealing interface will be created when the thickened portion 34 of thesealing element 33 is expanded to fit over the shaft with excellentoperational results obtained thereby. One particular advantage derivedin connection with the standardized casings of FIGS. 1 and 2 is theabsolute minimization of the amount of fluorocarbon material required,with the attendant reduction in manufacturing costs. This can be bestappreciated by a consideration of the figures shown wherein the line ofshaft contact occurs intermediate the terminal portion of the shortexclusionary element and the inside diameter of the seal mountingmember. Thus the differential diameters of the sealing element 24 or 33can be minimized to conserve the amount of fluorocarbon used withoutaffecting the excellence of the sealing action. The use of a narrowsection of fluorocarbon also serves to reduce the influence of the greatdifferential in thermal expansion coefficients between the fluorocarbonand metal elements.

A further advantage derived from the use of double lip constructionsshown is that the exclusionary seal member will serve as a gasketingmember for the fluorocarbon packing as well as a separate seal toprevent foreign material from entering the packing assembly. Asillustrated in FIG. 1, the exclusionary sealing member is firmly bondedin a flashfree manner to the seal mounting member and extends asuflicient distance into the groove to provide a resilient backing forthe fluorocarbon sealing element.

Referring now to FIG. 3, the seal 40, illustrated in section, has theusual cylindrical press fit portion 41 and radially extending portion 42providing a pair of axially facing radial faces 43 and 44. The radiallyextending portion 42 is curled or rolled at its inner periphery into aU- shaped inner peripheral portion 45 to clampingly receive a secondannular member or an inner cup 46 to define a seal mounting groove 47.The inner cup 46 is provided with generally radially extending legportions 48 and 49 to form the sides of the groove 47. The leg portion48 is received in abutting engagement with axially facing radial face 44and is clamped thereto between the outwardly extending legs of theU-shaped peripheral portion 45. An exclusionary member 50 is bonded tothe U- shaped portion 45 with a thickened portion extending upwardlyinto the groove and overlying the juncture or joint between the innercup 46 and the terminus of the U-shaped flange 45. A fluorocarbonsealing element 51 overlies the thickened portion as it extends into thegroove 47. The mouth portions of the groove are defined by the raisedportion 52 and radially extending leg portion 53, and are offsetradially, for purposes to become apparent. The thickened portion of theexclusionary member 50 in the region of the raised portion 52 providesan abutment surface for the sealing element 51.

A pressure flange 54, similar in construction to the one defined inconnection with FIGS. 1 and 2, extends through the mouth portion intothe groove 47 terminating short of the lower extremity thereof. When theradially extending leg portion 49 is curled over to engage the outerperipheral portion of the pressure flange 54, pressure is applied to thesealing element 51, forcing it axially against the thickened portion ofthe exclusionary member 50 to provide a fluidtight internal gasket.Exlusionary member 50 may be bonded to the seal mounting member by anovel flashless molding technique mentioned in connection with FIGS. 1and 2 to be completely described in detail below. The sealing element 51may take various forms, for example it may comprise an annular washerhaving a thickened inner peripheral portion, with the preferred formshaving an inner diameter slightly less than the shaft of intended use.

A modified form of seal is shown in the view of FIG. 4 embodying acasing 55 formed in the shape of the casing of FIG. 3. The embodiment ofFIG. 4 utilizes a separable exclusionary member 56 having an outerperiphery received within the groove 57, which is constructed like thegroove 47 of the embodiment of FIG. 3. In the free state, the outerperiphery of the exclusionary sealing member 56 will take the formindicated in dotted lines at 58, and as clamping force is applied atassembly, the elastomer properties thereof permit the outer peripheralportion to assume the position shown in solid lines.

A thin fluorocarbon washer 59 is held within the groove in radial faceto face abutting engagement with the exclusionary member 56 by means ofa pressure flange 60. The clamping action exerted by the pressure flange60 is of the same form as described in connection with FIGS. 1-3 in thata force couple is created by the opposite forces generated at the mouthof the mounting groove formed by the raised portion 61 and the radiallyextending leg portion 62. Substantial benefits are obtained through theuse of the foregoing designs; in that the same casing can be used tomount seal members of different materials, hardness, etc., as well aspermit ing a choice of one or more lip designs up to the time ofassembly. It is contemplated that environmental factors in the intendedsealing application will ultimately dictate the range of availablechoices. In any event, the foregoing designs are extremely versatile,permitting the sealing lip types to be selected at assembly. Thus amanufacturer can make up a number of subas-sembly blanks and delayassembly until such time a customer orders a particular type of sealmember. Obviously, with the built-in versatility inventories can besubstantially diminished.

The embodiment of FIGS. 3 and 4 represents a modification of theconstructional concepts illustrated in FIGS. 1 and 2. While theembodiments of FIGS. 1 and 2 are quite satisfactory in certainapplications, the embodiment of FIGS. 3 and 4 provide an added advantagein the form of a minimization of metal strain, adapting them for usewith a wider range of shaft and bore sizes. Moreover, the two piececonstruction allows selection of diverse thicknesses of metals for theouter casing and inner cup which presents additional advantages. Inapplications in which the radially extending flange is of greatdiameter, a thickened inner cup may be used to lend rigidity thereto toinsure perfect concentricity in operation. Still further, in theembodiment shown, the use of a pressure flange results in two keyoperational features which are: (1) a neck contact point for rigidityand flatness with (2) a flexible action external from the gasket pointswhich provide a sustained loading on the packing( s). The importance ofthis cannot be overstressed since an oil seal, in order to be effective,must seal perfectly at two areas if it is assumed that the seal mountingmember is received in the cooperating bore in a fluidtight manner. Thelip contacting portion with the rotating or reciprocating s'haft mustprovide one sealing point, while the other must be at the area ofengagement of the seal element and its mounting member. The latter hasbeen alluded to above as the gasket area since the sealing element actsas a gasket at this point.

A further benefit derived from the use of the two piece seal mountingmember resides in allowing the outer she-ll thickness to be increased tothe point adequate for rigidity without increasing the possibility ofcracking at the bending region. In this instance the inner cup may bemade very thin to minimize and control bending stresses when thefluorocarbon element is clamped therein. In one concrete embodiment theseal mounting member had an inner cup thickness of ten thousandths of aninch whereas the outer portion was thirty thousandths of an inch inthickness, thus illustrating the flexibility of the design.

The embodiments of FIGS. 4A and 48 further demonstrate the flexibilityof the seal mounting member described above. It is to be understood thatthe outer periphery of the casing can be of any desired form, forexample it may be provided with an axially extending flange portionterminating in a radially inwardly turned radial flange such as shown inthe embodiments of FIGS. 14.

In the fragmentary portion illustrated in FIG. 4A the seal mountingmember 63 mounts an inner cup member 64 in a manner which will bespecifically described hereinafter. The inner cup defines a groove 65receiving the outer peripheral portion of a fluorocarbon sealing element66. The assembly as illustrated requires a minimum number of elements,these being the seal mounting member 63 having a short extruded neckcarrying a light gauge inner cup or stamping 64 with the height thereofbeing accurately controlled, and a fiat fluorocarbon washer. The spacingon the U-shaped portion receiving the inner cup member 64, permits theneck of the seal element mounting member 63 to curl on a sufficientlylarge radius in order to eliminate the danger of cracking at the insidediameter during the forming thereof.

When the inner cup 64 is curled over in the manner shown to engage theseal element 66, a controlled bend point on each side of the sealelement is established. The bend point on the outside is controlled bythe die rolling over the inner cup 64 while the inside bend point iscontrolled because the inner st-amping is made to accurately controlleddimension. A generous radius is provided on the inner end -67 of theinner cup 64 which discourages any tendency for the sharp edge of theinner stamping to cut into the fluorocarbon at the bend point. Areservoir of inverted tear drop cross section is developed inside theinner cup to provide ample volume for internal extrusion of thedisplaced material resulting from the clinching action. The particularimportance of this is clearly pointed out in th cop-ending applicationalluded to hereinbefore.

FIG. 4B illustrates a construction similar to that of FIG. 4A, however aflat pressure washer is included. As pointed out with respect to FIG. 4Athe manner of forming the subassembly will be described completelyhereinafter. The basic elements of the construction of FIG. 4B includethe seal element mounting member 63' (shown fragmentarily), inner cupmember 64' forming a groove 65' which receives a sealing element 66. Afiat pressure washer 68 is clamped by the inner cup 64' in radialengagement with the sealing element 66'. The pressure washer 68' isformed of light gauge material and made of a higher hardness of steelthan is normally used in the seal stampings forming the seal elementmounting member .for good clamping action. The inner cup member has awall portion 67' which is slightly shorter than the design shown in FIG.4A.

In the illustrated assembly, the open end of the stamping is curled overthe outer edge of pressure washer. This action causes the pressurewasher to deform a slight amount as shown, establishing the tendency forthe pressure washer to return to its original flat state. This resultsin a pressure on the fluorocarbon packing in the area of the curledinner periphery of the seal mounting member 63' to provide for excellentinternal gasket action.

FIGS. 5-8 illustrate the step-by-step method of manufacturing the sealof FIGS. 3 and 4 which also adds to the uniqueness thereof. The sealelement mounting member takes the form of a generally L-shaped section71 having an axially extending inner peripheral portion 72. As seen inFIG. 6 an inner cup 73 is positioned within the axial portion 72 whichis curled over to form a U-shaped peripheral portion shown in solidlines at 76 in FIG. 6 (dotted lines 74, FIG. 5). The dotted lines 77 onthe inner cup 73 illustrate a modified shape which the inner cup maytake without impairing the quality of the finished product. A clearance78 is provided between the radially extending portion of the inner cup73 and the outer casing 71 for purposes to become apparent.

In FIG. 7 the inner cup has been deformed into flat engagement with aradially extending wall portion 79 on the outer casing 71, suchdeformation occurring during the molding of lip 80 on the U-shapedperipheral portion 81. At this stage of manufacture, the inner cup 73has an axially extending flange portion 82, which permits insertion of afluorocarbon packing 83 of the desired shape and size along with anannular pressure flange 84. The axially extending flange 82 is thenrolled over to clamp the seal element and pressure flange as shown inthe completed assembly of FIG. 3. If the seal of FIG. 4 is to bemanufactured, the inner cup is formed as shown in FIG. 7 with the moldedlip 80 omitted. In order to fabricate the design illustrated in FIG. 4,the packings are stacked in the manner illustrated in FIG. 8, and theflange 82 is curled over to clamp the elements fluidtightly together ina single manufacturing step.

FIGS. 9-12 are graphic representations of the various configurationsthat the seal mounting member may take for various forms of sealelements. The seal mounting member is of standardized construction tohold single lip constructions, and double lip designs having eithermolded or separate lips, in combination with a thin fluorocarbon sealingelement of desired dimensions. In FIG. 9 the casing 85 has been formedto a generally L-shaped configuration like the embodiment of FIG. 5,having a U- shaped internal peripheral portion 86 which curls rearwardlytowards the outer peripheral portion of the seal element mounting memberterminating in an axially extending flange 87. If it is desirable toutilize a single sealing element such as shown in my copendingapplication, Ser. No. 178,390 filed Mar. 8, 1962 or a single sealing lipconstruction in combination with a clamped exclusionary member such asshown in FIG. 2, the seal mounting member will be further processed toinclude bending the leg portions of the U-shaped portion into mutualengagement as at 88. The seal element(s) may then be positioned andclamped by rolling over the flange 87 to the final position shown inFIG. 2.

Assuming it is desirable to manufacture a seal having a molded exclusionmember, the seal mounting member 85 of FIG. 9 is placed in a mold aswill be hereinafter described more fully, and the lip 89 shown in FIG.11 is molded as shown, with the bending step being performed in themolding process. A thin sealing element 90 may be positioned as shown inFIG. 12 along with a pressure flange member 91 within the annulusdefined by the axially extending flange portion 87. A suitable fixtureholds the seal mounting member while the flange 87 is rolled over toassume the configuration shown in FIG. 1, completing the seal assembly.

The various forms of seal mounting member constructions shown in FIGS.-12 lend economy to the manufacture of a wide range of versatile seals,with each insuring that the internally gasketed portion will remainfluidtight over a wide range of temperatures and pressures. The internalgasketing of the sealing element is achieved through the use of thenovel groove construction employing a wider base portion than the mouthportion, allowing ample volume for any material extruded or dis placeddue to the clamping action at the mouth portion. The clamping action iscontinuously exerted, which is particularly important in materials whichare susceptible to compression set, cold flow or include thermoplasticcharacteristics which would tend to reduce the gasket pressure resultingfrom the build-up of kinetic energy at the time of clamping.

More particularly, in the fluorocarbon sealing elements which arenecessarily very thin, the margin between suflicient compressiontoprovide a fluidtight internal gasket and that to shear thefluorocarbon packing is quite narrow when compared with the more commonsealing materials. Thus, it is essential that the clamping pressureapplied to the sealing components must be accurately controlled and theassembly set-up must be held to most exacting tolerances if the internalgasketing action is dependent on the kinetic energy in the compressedfluorocarbon sealing element. The use of a pressure flange which isloaded around the outer peripheral portion by the clamping action servesto provide a constant force at its internal periphery defining a bendpoint in the fluorocarbon sealing element, as well as providing constantpressure to insure a fluidtight internal gasket. In the double lipdesigns, the exclusionary member is positioned so as to overlie a raisedportion of the mouth to provide a resilient backup member co-operatingwith the pressure flange to maintain fluidtightness under the mostadverse conditions without impairing the flexing action of the sealingelements held thereby. Obviously, this function could also be achievedby a resilient backup washer or coating which does not perform a scalingfunction.

As pointed out above, the outer periphery of the pressure flange islesser in diameter than the base portion of the groove of theco-operating seal mounting member.

When the outer peripheral portion of the pressure flange is deflectedunder the clamping force, it causes a further reduction in the outsidediameter, causing the radially extending portion thereof to take agenerally spherical shape serving to reduce the force transmitted to thesealing element. While in some instances this may be desirable in orderto lend rigidity to the pressure flange, in other cases it isundesirable due to the reduction in available clamping force.

The undesirable aspects were overcome in a manner shown in FIG. 13wherein a series of radially extending notches 92 were provided in thefoot or radially extending portion 83 of the pressure flange 94. Thenotches were closely spaced so that on clamping, deflection took placeon a series of straight lines (indicated in dotted lines at 95) betweenthe notches minimizing any tendency for the foot portion 93 to take arigid spherical shape.

This may be more clearly observed in FIG. 14 which shows the pressureflange in solid lines in the free state, and in dotted lines 96 in theclamped state, with the overall reduction in diameter represented by thedifferential between D1 and D2. While a heavier gauge flat washer may besubstituted for the generally L-shaped design of the pressure flange, ithas been desirable to make it of the shown configuration since undergeneral techniques the stamped out inner portion would in most instancesbe scrap. Obviously, a thinner gauge of metal may be use for thepressure flange when it is formed in the L- shaped configuration shownwith the attendant saving of material and reduction in manufacturingcosts.

The manner in which the exclusionary element is molded in a flash freemanner to the unified casing will now be explained with reference toFIGS. 15 and 16. The seal mounting member of FIG. 9 is positioned in thelower half of a mold with the axially extending flange portion inabutting engagement with a cylindrical surface 101, and the U-shapedperipheral portion 86 extending into the mold cavity 102. The upper halfof the mold 103 is provided with a seal mounting member surface engagingportion 104 which has a cavity 105 terminating substantially inopposition to a circular line on the other leg of the U-shaped memberindicated at 106. As illnstrated in FIG. 15, the mold is in the initialcontact position with the surface 104 in abutting engagement with theradially extending flange portion of the cup. The lower mold halfcenters the cup by the cylindrical surface 101 being in circumferentialengagement with the inner peripheral portion of the flange 87, toprovide concentricity of the stamping in relationship to the center lineof the mold. The prepared elastomeric material is loaded in the centralregion of the mold cavity when the mold is entirely open. As the moldcloses, the material is extruded outwardly in the mold cavity 102partially filling the cavity when the mold initially contacts the sealmounting member 85. Continuous axial travel of the mold after initialcontact with the seal mounting member serves to completely fill the moldcavity with a building up of suflicient internal pressure to form amechanically rigid fluidtight bond. That is achieved by literallyfilling the mold cavity before axial movement of the mold is completed.Inasmuch as the elastomers are relatively incompressible, the finalincrement of mold travel requires some extrusion of material out of themold cavity through provision of suitable relief grooves.

It is essential, in order to have a flash free finished product, thatthe contact pressure at the junction of the mold and seal mountingmember on opposite sides thereof be of sufiicient magnitude to act as abarrier to the elastomer flow, bearing in mind that considerablepressure is generated when the volume of the mold cavity is reduced tominimum. This becomes more apparent on examination of FIG. 16 whichshows the mold at the closed position. Contact pressure is generatedacross the surface 104 terminating in a circular line 107 on the outerface of the seal mounting member, and over a generally point-likesurface 108 on the inner side of the seal mounting member. The axialtravel of the mold causes the leg portions of the U-shaped internalperipheral portion to merge together forming the axial raised mouthportion described above.

A great appreciation of this coaction will be had by examination of theenlarged view in FIG. 17. The solid lines illustrate a fragmentaryportion of the casing 85, with the mold in the position described inconnection with FIG. 15, while the dotted lines indicated by primenumerals indicate the final position of the seal mounting member whenthe mold has completed its travel. The enlarged view showns thepoint-like contact at 106 to define a sharp cutolf to avoid any flashwhatsoever. It is to be appreciated that as the mold travels from theinitial contact position to closed position, the stamping is reformed bythe mold. The resisting force of the stamping to the reforming actiongenerates suflicient pressure against the mold halves along the areasnoted to insure a flash free finished product. Since the force whichreforms the seal mounting member acts essentially in an axial alignmentwith the reacting force, there is no danger of distortion of the outerperipheral portion of the seal mounting member, and stretching of themetal is maintained at a minimum. It is obvious that the cutoff linesmay be varied slightly without adverse effect so long as the resistingforce of the mounting member is sufficient to maintain mold engagementin opposition to the elastomer pressure.

The seal mounting member defined in connection with FIG. 6, is shown inFIG. 18 as being positioned in a mold of identical construction to themold of FIG. 13. The seal mounting member is illustrated with the innercup 73 taking the arcuate form illustrated in dotted lines at 77 in FIG.6. However it may take the form shown in solid lines also withouteffecting the quality of the finished product. The inner cup 73 isprovided with an axially extending portion for engagement with acircumferential surface 101 of the lower mold 100.

In the position of initial contact shown, the upper mold half 103contacts the radially extending face on the seal mounting member over afairly broad area terminating in a circle 105. The U-shaped innerperipheral portion 76 is positioned concentrically within the moldcavity with the terminal point being well within the cavity andconcentric thereto, due to the snug relationship between the flange 73and the lower mold 101.

As the mold halves 100 and 103 move to the closed position, the innercup 73 is reformed to provide an annulus substantially L-shaped in crosssection. The contact pressure between the subassembly of the sealmounting member before reformation and the mold is derived from theforce required to reform the inner cup 73. The reformation takes placein the mold to the degree that the inner cup surface impinges againstthe radial face 110 of the seal mounting member. Mold material flowsaround the U-shaped peripheral portion and over the junction with theinner cup 73 forming an additional seal as well as firmly adhering tothe stepped surface of the joint.

It is evident that the outer diameter of the seal mounting member willvary over a wide range to fit machine housing bores of variousdiameters. The molds shown will accommodate various shapes and sizeslimited only by the internal diameter. For example, the seal may beformed as illustrated in dotted lines at 111 with a necked radial flangeportion to protect the molded lip during later handling and shipment.Also it is possible to use the necked flange 111 as a centering meansduring molding if desired. The molding technique described is notlimited to the single lip construction shown, and additional lips may beformed by providing an additional cavity in the mold. In all cases thecharge of mold material is reduced considerably to insure minimizing ofmanufacturing costs.

The seal shown in section in FIG. 20 comprises a seal mounting member120 and a sealing element 121. The seal mounting member 120 is of theform of the embodiment of FIG. 6 prior to molding the sealing element121 thereon, with the original configuration being represented by dottedlines 122. After the sealing element 121 has been molded thereto, theaxial flange 122 on the inner cup 123 assumes the configuration shown at124 with the reformation occurring in the molding process.

The inner peripheral portion 125 of the seal mounting member is engagedby one of the mold halves to insure proper centering and with suflicientpressure to insure a clean cutoff line in accordance with the flashlessmolding procedure described above. The axially extending flange portion122 of the inner cup 123 is reformed to the position shown at 124 by thecoacting mold half to provide a clean, sharp, flash free cutoff betweenthe mold material of the lip portion and the seal mounting member.

The modification of FIG. 20 is exemplary of the wide variations of usesof the seal mounting member subassembly shown at FIG. 6. The inner cup123 may be diverse thickness with respect to the remaining portion ofthe seal mounting member 120 for reasons previously noted.

A feature which is exceedingly important in each of the foregoingdesigns, is that each is conductive to universal molding withoutrequiring the inner peripheral region of the seal mounting member to bebent at an angle during the molding process as in known techniques.Bending of this magnitude is objectionable since it causes distortion ofthe outer periphery of the seal mounting member, ultimately resulting inan imperfect seal when the finished assembly is mounted in the bore of amachine housing or the like. Further, the thickness of metal in each ofthe present designs lends itself to sturdy seals, even though the gaugeof the material practically speaking, is very light and the coststhereof maintained at a minimum. In addition, the novel seal mountingmember utilizes a relatively standardized stamping for a subasssemblywhich forms the basis for a wide range of diverse seal types, which mayultimately be selected or chosen at the time of assembly. Thus, therequirement to have huge inventories is obviated and orders for aparticulartype of seal can be fulfilled by completion of the finishedproduct through performing a single assembly step.

It is not intended that the illustrated embodiments and languageemployed in describing the same be limiting, inasmuch as such was donein the interest of brevity and clarity of description. It will becomeimmediately obvious to those skilled in the art, that certainmodifications and variations of the invention may be made withoutdeparting from the spirit and scope thereof, and therefore only suchlimitations should be imposed as are indicated in the appended claims.

I claim:

1. The method of forming a seal comprising the steps of forming a metalannulus which is generally L-shaped in section having an axiallyextending abbreviated flange, curling said flange in a radially outwarddirection so as to be substantially parallel to one leg of said L-shapedsection, and further curling said flange in an axial direction therebydefining a seal mounting flange, inserting said annulus in a charged twopart mold having a seal forming cavity therein, positioning the axiallyextending portion of said seal mounting flange in snug circumferentialengagement with one part of said mold, thereby placing the curledportion within the mold cavity, closing said mold parts to engage saidL-shaped annulus on one side and said portion of said seal mountingflange on the other to deform a portion of said seal mounting flangetowards one leg of said L-shaped annulus while simultaneously molding asealing lip about said seal mounting flange.

2. The method of claim 1 including the steps of removing said annulusfrom said mold, inserting a second sealing element within the axially,extending portion of said seal mounting flange, positioning metalannulus over said second sealing element and curling said axial flange 11 over to form a groove to hold said second sealing element and saidmetal annulus in abutting fluidtight engagement.

3. The method of forming a seal comprising the steps of forming anannular metal seal mounting member having a radially extending faceportion and an axially extending portion, providing an annular inner cupcapable of being inserted into said member and having an axial flangeportion joined to a radial flange portion, positioning said inner cupwith a portion of the radial flange portion abutting said radiallyextending face portions in the region of said axially extending portion,curling said axially extending portion over said radial flange on saidinner cup to maintain said radial flange and said radial portions inengagement, inserting said seal mounting member in a charged,seal-forming, two-part mold, positioning said axial flange in snugengagement with a peripheral portion on said mold with the radial flangeof said inner cup extending Within the mold, closing said mold to engagesaid radial face portion with one part and said radial flange with theother part, continuing the closing of said mold to bring substantiallyall of said radial flange on said inner cup into abutting engagementwith said radial face portion while simultaneously molding a sealingelement thereto.

4. The method of claim 3 further including the steps of removing saidseal mounting member and molded sealing element from said mold,inserting a second flat washer-like sealing element within the confinesof said axial flange on said inner cup, placing a pressure flange oversaid second sealing element and curling said axial flange in a radialand axial direction to clamp said pressure flange and sealing elementwithin a groove formed thereby.

5. A method of molding and attaching an clastomeric sealing element toan annular rigid metallic seal mounting member having a generally radialportion with a U-shaped peripheral portion to provide a pair ofoppositely directed generally radially extending surfaces, saidelastomer being attached to said seal mounting member in a flash freemanner, which method comprises applying pressure in one directionagainst one of said surfaces of said seal mounting member adjacent theU-shaped peripheral portion over an area terminating in a circular lineradially spaced from the base of said U, applying pressure to the otherface in a generally axial direction in a circular line adjacent saidU-shaped peripheral portion, applying elastomeric material to both ofsaid surfaces of said seal mounting member, said elastomer extendingfrom one of said circular lines to the other of said circular lines soas to bond said elastomer about the base portion of said U-shapedperipheral portion, said elastomer terminating at said lines in a flashfree manner.

6. The method of claim 5 including the step of deforming one upstandingportion on said U-shaped portion towards the other upstanding portionimmediately prior to the application of elastomer to said U-shapedportion.

References Cited UNITED STATES PATENTS 3,090,996 5/1963 Reishenbach etal. 29527 3,122,116 2/1964 Hagmann et al. 29528 X 3,276,114 10/1966Blaurock 29527 3,276,115 10/1966 Hansz 29527 3,352,566 11/1967 Kennedy29527 X JOHN F. CAMPBELL, Primary Examiner.

PAUL M. COHEN, Assistant Examiner.

1. THE METHOD OF FORMING A SEAL COMPRISING THE STEPS OF FORMING A METALANNULUS WHICH IS GENERALLY L-SHAPED IN SECTION HAVING AN AXIALLYEXTENDING ABBREVIATED FLANGE, CURLING SAID FLANGE IN A RADIALLY OUTWARDDIRECTION SO AS TO BE SUBSTANTIALLY PARALLEL TO ONE LEG OF SAID L-SHAPEDSECTION, AND FURTHER CURLING SAID FLANGE IN AN AXIAL DIRECTION THEREBYDEFINING A SEAL MOUNTING FLANGE, INSERTING SAID ANNULUS IN A CHARGED TWOPART MOLD HAVING A SEAL FORMING CAVITY THEREIN, POSITIONING THE AXIALLYEXTENDING PORTION OF SAID SEAL MOUNTING FLANGE IN SNUG CIRCUMFERENTIALENGAGEMENT WITH ONE PART OF SAID MOLD, THEREBY PLACING THE CURLEDPORTION WITHIN THE MOLD CAVITY, CLOSING SAID MOLD PARTS TO ENGAGE SAIDL-SHAPED ANNULUS ON ONE SIDE AND SAID PORTION OF SAID SEAL MOUNTINGFLANGE ON THE OTHER TO DEFORM A PORTION OF SAID SEAL MOUNTING FLANGETOWARDS ONE LEG OF SAID L-SHAPED ANNULUS WHILE SIMULTANEOUSLY MOLDING ASEALING LIP ABOUT SAID SEAL MOUNTING FLANGE.